Fatty adds saturation

Fatty Adds in Food Saturated Versus Unsaturated... 

More than LOO different fatty acids are known, and about 40 occur widely. Palmitic acid (C ) and stearic acid (Cjy) are the most abundant saturated fatty adds oleic and linoleic acids (both Care the most abundant unsaturated ones. Oleic acid is monounsaturated since it has only one double bond, whereas linoleic, linolenic, and arachidonic acids are polyunsaturated fatty acids because they have more than one double bond. Linoleic and linolenic... 

Quom has a higher ratio of polyunsaturated to saturated fatty add s than the other foods listed. It contains no cholesterol. The amino add profile is similar to that of other protein foods. It is slightly lower in methionine and cysteine content. 

These are the esters of long-chain fatty acids and long-chain fatty alcohols. Usually, only the alcohols are saturated and monoenoic, whereas the fatty adds may be more highly unsaturated, as in most marine waxes. They are found in both animal and plant tissues as well as in some microorganisms. They are quite common in insects. They reserve energy in aquatic animals, aid in echolocation, and play a vital role in waterproofing. 

Fatty acids of plant, animal, and microbial origin usually consist of an even number of carbon atoms in the straight chain. The number of carbon atoms of fatty adds in animals may vary from 2 to 36, whereas some microorganisms may contain 80 or more carbon atoms. Also, fatty adds of animal origin may have one to six ds double bonds, whereas those of higher plants rarely have more than three double bonds. Fatty adds also may be saturated, monounsaturated (monoenoic), or polyunsaturated (polyenoic) in nature. Some fatty acids may consist of branched chains, or they may have an oxygenated or cyclic structure. 

Saturated-, unsaturated fatty adds, triglyceride from interesterification products silicalite-1 2-Heptanone/ acetone [191]... 

In the vertebrates, biosynthesis of fatty acids is catalyzed by fatty add synthase, a multifunctional enzyme. Located in the cytoplasm, the enzyme requires acetyl CoA as a starter molecule. In a cyclic reaction, the acetyl residue is elongated by one C2 unit at a time for seven cycles. NADPH+H is used as a reducing agent in the process. The end product of the reaction is the saturated Cie acid, palmitic acid. 

Data dted by Garke (24) indicate that fatty add content may be a good indication of lipid fractionation by SFE. He found that saturated fatty adds were reduced 72% and unsaturated fatty adds reduced by 63% compared to the unextracted control. Cholesterol was reduced by 76% to an average of 41.6 mg/100 g in the extracted meat residue (24). 

ALIPHATIC COMPOUND. An organic compound that can be regarded as a derivative of methane. CH4. Most aliphatic compounds are open carbon chains, straight or branched, saturated or unsaturated. Originally, the term was used to denote the higher (fatty) adds of the C H Oj series. The word is derived from the Greek term for oil, See also Compound (Chemical) and Organic Chemistry. 

The chemical composition of camauba wax comprises 84 -85% of alkyl esters of higher fatty adds. Of these esters only 8-9% (wax basis) are simple esters of normal acids. The other esters are acid esters 8-9%, diesteis 19-21%, and esters of hydroxylated acids 50-53% (was basis) of which about one-third are unsaturated. It is the hydroxylated saturated esters that give camauba its extreme hardness, whereas the esters of the hydroxylated linsatiiraled fatty adds produce the outstanding luster to polishes. 

R. Brandes, R, K. Ocltner, R. A, Wfcifiagei and N. Lysenbo. Specific and saturable binding of albumin to rat adipocytes Modulation by epinephrine and possible role in free fatty add transfer. Biochenu Biopkys. Res. Cotnmuit. 705 821-827 (1982),... 

The fatty adds of common triglycerides are long, unbranched carboxylic acids with about 12 to 20 carbon atoms. Most fatty acids contain even numbers of carbon atoms because they are derived from two-carbon acetic acid units. Some of the common fatty acids have saturated carbon chains, while others have one or more carbon-carbon double bonds. Table 25-1 shows the structures of some common fatty acids derived from fats and oils. 

LAFETINA eg, REEP B, GANONG BR Bell RM. Exogenous sn-1,2-diacyIglycerols containing saturated fatty adds function as bioregulatcs s of protein kinase C in human platelets. JBiolChem269 1358-1365,1985. 

The nature of a fatty add influences its fate. Short- and medium-tdiain fatty adds tend to be oxidised immediately to carbon dioxide, rather than deposited as TGs or phospholipids. The presence of double bonds ("unsaturations") in long-chain fatty adds influences the immediate fate of the add. Some evidence suggests that unsaturated fatty acids, such as 18 2, tend to be oxidized at a slightly faster rate in the hours following a meal than saturated fatty acids, such as 18 0 (Jones et al., 1985, Jones and Schoeller, 1988). More specifically, about 2% of a test meal of 18 0 may be oxidized in the 9 hours toUowing Ingestion, whereas about 10% of a test meal of 18 2 may be oxidized in the same period, The mechanisms that influence the fates of unsahirated and saturated fatty adds are only beginning to be understood. 

A typical American diet contains about 40% of its total energy content as fat. About half this energy is in the form of saturated fatty acids, one-fourth as monounsatu-rated fatty adds, and one-fourth as polyunsaturated fatty adds (PUFAs) (Ginsberg et dl., 1990). The quantity and nature of dietary fats carx influence the lex. d of plasma cholesterol. A reduction in total fat from the typical 40% of energy intake to 30% can result in a decrease in plasma cholesterol. 

FEGURE 635 Conversion of stearic acid to an IS I fatty add. Through foririation of a double bond, stearic acid a saturate, is converted to acid (1S 1), a rnonounsaturate. 

In addition to chain elongation, fatty adds are modified by the introduction of double bonds (desaturation). Enzymes, called desaturases, catalyze the synthesis of imsaturated fatty adds. They can use saturated or partially unsaturated fatty acids as substrates. A -Desaturasc, for example, catalyzes the introduction of a double bond between carbons 9 and 10 of a fatty acid (counting from the carboxylic acid end). Thrxjc examples of reactions of A-desaturases are shown in Figure 9.95. 

Palmitic acid (16 0) is the primary saturated fatty acid in most diets. This compound constitutes about 25% of the fatty acids of beef or pork fat, but only 6-10% of the fatty adds of sunflower, safflower, peanut, or soy oils (see Table 6.8). Dietary palmitic add increases LDL-cholesterol (Gnmdy and Denke, 1990). Myristic add (14 0) is present at high levels in butterfat and in the "tropical oils" palm oil and coconut oil. Although m)nistic add elevates LDL-cholesterol, it is generally a rather minor component of the diet. Stearic acid (18 0) is also a major component... 

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